The worst accident involving lightning in living memory happened in December 1963, when a lightning bolt hit the fuel tanks of a Boeing 707 flying over Maryland in the United States, claiming 81 lives.

More recently, 17 people were killed in May 1976 when a Boeing 747 operated by the Iranian air force, was stuck by lightning as it approached Madrid airport.

Immediately after the Maryland crash the Federal Aviation Administration ordered that commercial aircraft be fitted with a device known as an electrical discharge wick.

In layman's terms, it is a piece of metal on the wingtips of an aircraft which dissipates the electricity from a lightning strike away from the fuselage itself.

Modern aircraft, which are made of aluminium, are also considered more capable of resisting lightning bolts, which can be in excess of 300,000 amps.

But there are some concerns that the latest generation of aircraft, which use a higher proportion of carbon composite, may be more vulnerable to storm damage.

A safety risk, no matter how remote, remains and the possibility of damage to the electronics can never be discounted completely.

Considerable effort is still devoted to trying to avoid bad weather where possible.

Paul Hayes a director of Ascend, an aviation consultancy, said: "Pilots have a weather briefing before take off.

"Also aircraft are equipped with weather radar which enables a pilot to know what is coming up."

But that does not guarantee they can avoid turbulence, although this is normally considered more of a factor on take off and landing rather than when they have reached their cruising altitude.

"Turbulence can be extremely disturbing, especially for the passengers," said Mike O'Kane, a pilot with 30 years experience.

"It has been so bad, especially in equatorial regions, that you can't read the instruments because your body is being shaken up so much.

"Normally you get turbulence when there are thunderstorms and strong up and down currents in heavy cloud. Radar is very good at spotting these clouds at night.

"But there is also clear air turbulence, which are normally associated with jet streams which can reach 150mph. They are harder to spot and are similar to a fast flowing stream running into a still river."

But even turbulence should not have caused a plane to disappear off the radar, experts said.

"These aircraft are designed to go through very powerful turbulence without being put at risk. Equally, they receive lightning strikes all the time, and the airframe is carefully designed to dissipate the electrical charge," said Stewart John, Fellow of the Royal Academy of Engineering and past president of the Royal Aeronautical Society

"This is a 'fly-by-wire' aircraft – in other words it is completely dependent on its electronics to operate. But it has a huge amount of built-in-redundancy in terms of separation of wiring, backup power supply etc. Whether the lightning and turbulence together caused a catastrophic fault on this occasion we won't know for some time."